The present invention relates generally to attachments for machine tools. The invention concerns a housing assembly that is adapted and retrofitted for use with vertical milling machines to measure the vertical travel, or milling depth, of the quill mechanism. More particularly, the invention concerns a stop mechanism for engagement with a threaded rod.
Vertical milling machines are known in the art and a number of different types of milling machines are commercially available. By way of example, Bridgeport(copyright) and R F Rong Fu(copyright) produce various models of milling machines. These commercially available milling machines are generally classified into two main divisions, vertical and horizontal. In the horizontal milling machines, the cutter is horizontally mounted to a spindle and moves in a horizontal manner. Similarly, in a vertical milling machine, the cutter is vertically disposed and moves in a vertical fashion.
A conventional vertical milling machine generally includes a table on which a workpiece can be supported, and a quill that supports a tool or cutter for movement toward and away from the table for milling the workpiece. Typically, the table is adjustable within the horizontal plane from side to side and from front to back relative to the quill. Although many milling machines are manual, in the sense that adjustment of the table and movement of the quill is manually achieved, improvements in the art have been made for fully automated machines. These automated machines provide some advantages over manual machines, however, they are considerably more expensive for users. Moreover, they lack the versatility of manual machines.
In addition to the above, many of the manual, vertical milling machines commercially available provide an already attached manual measuring apparatus for determining the vertical travel, or milling depth, of the quill. By way of example, R F Rong Fu(copyright) milling machines provide a plastic assembly located on the face of the machine. The assembly comprises a housing attached to the milling machine and a moveable indicator attached to a quill shaft stop bar. The housing further has a rectangular hole which is centrally located thereon and a measurement scale surrounding the hole. As the quill is lowered and raised the indicator points to a corresponding measurement on the measurement scale, thereby informing a user of the approximate vertical movement or depth.
A disadvantage of the current measuring devices provided in milling machines is that they do not provide precise measurements. Typically, the units of measure on the devices are not small enough and one""s ability to properly bore holes and mill workpieces is restricted. An example of an industry that thus is restricted is the steel industry, in which machined parts must be milled to precise tolerances. The measuring units currently provided simply do not and cannot accurately measure pieces to ensure that certain hole depths meet those tolerances. Thus, a need exists for an apparatus which provides a precise measurement of the depth or vertical movement of a quill.
Currently, there exist some measuring devices which accurately determine the vertical movement of the quill. However, for various reasons, these devices are ineffective to accomplish the objects stated herein. For example, the Mitutoyo Corporation manufactures the Digimatic Quill Kit for vertical Bridgeport(copyright) milling machines and Bridgeport(copyright) type machines. The Quill Kit essentially is a retrofitted housing comprising a main scale, a digital display indicator attached to the front surface of the main scale, a rear support plate secured to the rear of the indicator, thereby securing the indicator to the main scale, a tapped hole mounting bracket which is attached to the scale, a base, a scale stop bar that is mounted to the rear plate, a scale stop bracket and a plurality of screws and washers. The Quill Kit unit is attached to a milling machine by first retracting the spindle of the machine and removing the quill wheel. Vernier scale screws of the milling machine are removed and the base is placed over the vernier scale. The vernier screws are replaced and the mounting bracket is attached to the base. The scale is attached to the mounting bracket by the scale stop bracket.
A disadvantage of the Quill Kit is that it is only useful for Bridgeport(copyright) type machines. The device simply cannot be used on other types of milling machines, such as the R F Rong Fu(copyright) models. Moreover, the Quill Kit is comprised of many unnecessary components. As such, it is expensive to manufacture.
Stops and guides for use on drilling, depth milling and other similar machinery are known, as are quick release nuts which provide for selective sliding or threading motion with respect to a threaded shaft. Guthrie U.S. Pat. No. 4,693,656 describes such devices. Current stops, as shown by Guthrie, have a spring which presses against the end of the release nut, causing the stop to remain in place. However, such arrangement is not sufficiently tight to prevent movement of the stop on the threaded shaft or rod.
Thus, it is clear that a need exists for an inexpensive, stop which can hold be tightly when desired, and which can be provide both coarse and fine adjustments, and which is simple and versatile, and readily retrofit for use with vertical milling machines, and which is readily removable.
The present invention is a quick adjusting stop nut for selective sliding coarse adjustment and rotational precision fine adjustment for rotatable engagement with a threaded rod or shaft in close tolerances, which provides stable precision engagement with the shaft, and which provides a positive locking mechanism.
The present invention is particularly useful with a retrofit apparatus for vertical milling machines which generally comprises a mounting cover, a main scale, an indicator, a rear plate, a plurality of hat clips, a plurality of screws, a quill stop bar, a set screw, a quill stop mount and a graduated rod. The main scale is slidably attached to the rear of the indicator. The rear plate is connected to the rear surface of the indicator by a plurality of screws with the scale displaced therebetween. The mounting cover of the present invention has a generally rectangular configuration. Further, the mounting cover has a generally elongated rectangular aperture, substantially and centrally located therein. The length of the aperture extends along the length of the mounting cover face. The scale, indicator, and rear plate are secured to the face of the mounting cover by a plurality of hat clips. The components are secured so that the indicator is fixed within the aperture of the mounting cover and slidably moves in concert with the quill.
Attachment of the assembly to the quill stop bar and quill stop mount is accomplished by screwing the rear plate to the quill stop bar and inserting the quill stop bar into an aperture in the quill stop mount. A graduated rod is provided for connection to the quill stop mount, thereby allowing the slide support and scale to slidably move up and down. The entire assembly is then fixed to a milling machine by a plurality of screws which are matingly inserted into a plurality of corresponding receiving holes located on the milling machine and the left and right sides of the mounting cover.
In an alternative embodiment, the invented retrofit generally comprises a mounting cover, a main scale, an indicator, a slide support, a clamp mount, a plurality of hat clips, a plurality of screws, a quill stop bar, a quill stop mount and a graduated rod. The main scale is slidably attached to the rear of the indicator. The slide support bracket is connected to the rear surface of the scale by a plurality of hat clips and screws which partially cover the ends of the front surface of the scale. The mounting cover of the present invention has a generally rectangular configuration. Further, the mounting cover has a generally rectangular aperture, having a substantially similar configuration as the indicator, located at the bottom end of its face. The scale, indicator, and slide support are secured to the mounting cover by a clamp mount, which is disposed between the indicator and the slide support. The components are secured so that the indicator is fixed within the aperture of the mounting cover.
Attachment of the assembly to the quill stop bar and quill stop mount of the alternative embodiment is accomplished by screwing the slide support to the quill stop bar and inserting the quill stop bar into an aperture in the quill stop mount. A graduated rod is provided for connection to the quill stop mount, thereby allowing the slide support and scale to slidably move up and down. The entire assembly is then fixed to a milling machine by a plurality of screws which are matingly inserted into a plurality of corresponding receiving holes located on the milling machine and the left and right sides of the mounting cover.
In another alternative embodiment of the present invention, the retrofit comprises a mounting cover, a main scale, an indicator, a rear plate, a hat clip clamp mount, a quill stop, a mount and a quill shaft. The aperture of the mounting cover is of a corresponding size to the indicator. The main scale is slidably mounted to the indicator by the rear plate. The indicator and scale are attached to the mounting cover by the clamp mount. In addition, the indicator and scale are fixed to the quill shaft and quill stop at the mount. Subsequently, the entire assembly is joined to the milling machine by a plurality of screws which connect the two by a plurality of corresponding holes located on the milling machine and the left and right sides of the mounting cover.
In a further embodiment of the present invention, a second generally elongated aperture is present along side the aperture. The second aperture is of a shorter length and runs parallel to the aperture. Displaced within the second aperture is a hard stop block having a T-bolt configuration. The hard stop block has an additional lock lever which, when engaged allows a user to set the block along the second aperture at a predetermined point. In operation, the user moves the hard stop block to a desired location on the second aperture and locks it in place. Once the quill is extended, the rear plate contacts the hard stop block and resists further extension. This feature allows the user to mill multiple workpieces at a consistent depth.
Accordingly, it as a principal object of the present invention to provide a stop nut for milling machines which accurately and tightly holds against vertical movement of a quill during operation.
A further, and more particular, object of the invention is to provide a stop nut for a threaded rod that can be adapted and retrofitted to various machines.
Another object of the invention is to provide a stop nut assembly which allows measuring the precise vertical movement of a quill or other device during operation, while holding tightly to prevent movement during operation.